Color cathode ray tube

Abstract

A color cathode ray tube equipped with an in-line electron gun for emitting three electron beams includes a main lens made up of two cylindrical electrodes arranged in a spaced relationship. Each of the electrodes has an opening and having therein a plate electrode with a beam passing area. The electrodes are given different voltages, wherein D and S have values in a region where all of the following inequalities are satisfied; S≦5.0 S<D, and 145.5≦55S-20D S being a beam spacing in mm between central axes of the three adjacent electron beams at the main lens, and D being a dimension in mm related to a distance of a center of at least one of the in-line arrangement of the three electron beams to an inner edge of at least one of the two cylindrical electrodes.

What is claimed is: 
     
       1. A color cathode ray tube equipped with an in-line electron gun comprising three cathodes for emitting three electron beams of an in-line arrangement toward a fluorescent screen, and a main lens for focusing said three electron beams on the fluorescent screen, said main lens comprising two cylindrical electrodes arranged in a spaced relationship in a direction of an axis of said tube, said two cylindrical electrodes having different voltages applied thereto, wherein the following inequalities are satisfied;   2S+14.6≦T≦25.3     S being a beam spacing in mm between central axes of said three electron beams at said main lens, and T being an outside diameter of a neck portion of a vacuum envelope housing said in-line electron gun which is larger than about 22.5 mm, wherein a distance from a center of a side electron beam to an inner wall of said neck portion at said main lens is at least about 4.8 mm.   
     
     
       2. A color cathode ray tube equipped with an in-line electron gun comprising three cathodes for emitting three electron beams of an in-line arrangement toward a fluorescent screen, and a main lens for focusing said three electron beams on the fluorescent screen, said main lens comprising two cylindrical electrodes arranged in a spaced relationship in a direction of an axis of said tube, said two cylindrical electrodes having different voltages applied thereto, wherein the following inequalities are satisfied;   2S+14.6≦T≦26.7     S being a beam spacing in mm between central axes of said three electron beams at said main lens, and T being an outside diameter of a neck portion of a vacuum envelope housing said in-line electron gun which is larger than about 22.5 mm, wherein a distance from a center of a side electron beam to an inner wall of said neck portion at said main lens is at least about 4.8 mm.   
     
     
       3. A color cathode ray tube equipped with an in-line electron gun comprising three cathodes for emitting three electron beams of an in-line arrangement toward a fluorescent screen, and a main lens for focusing said three electron beams on the fluorescent screen, said main lens comprising two cylindrical electrodes arranged in a spaced relationship in a direction of an axis of said tube, said two cylindrical electrodes having different voltages applied thereto, wherein the following inequalities are satisfied;   2S+14.6≦T≦28.1     S being a beam spacing in mm between central axes of said three electron beams at said main lens, and T being an outside diameter of a neck portion of a vacuum envelope housing said in-line electron gun which is larger than about 22.5 mm, wherein a distance from a center of a side electron beam to an inner wall of said neck portion at said main lens is at least about 4.8 mm.   
     
     
       4. A color cathode ray tube equipped with an in-line electron gun comprising three cathodes for emitting three electron beams of an in-line arrangement toward a fluorescent screen, and a main lens for focusing said three electron beams on the fluorescent screen, said main lens comprising two cylindrical electrodes arranged in a spaced relationship in a direction of an axis of said tube, said two cylindrical electrodes having different voltages applied thereto, wherein an outside diameter of a neck of a vacuum envelope housing said in-line electron gun is substantially 24.3 mm, and a distance from a center of a side electron beam to an inner wall of said neck at said main lens is at least about 4.8 mm. 
     
     
       5. A color cathode ray tube according to any one of claim 1 to claim 4, wherein at least one of said two cylindrical electrodes has an opening and has a plate electrode with a beam passing area provided therein. 
     
     
       6. A color cathode ray tube according to claim 5, wherein each of opposing ends of said two cylindrical electrodes comprises a common single opening for said three electron beams. 
     
     
       7. A color cathode ray tube according to claim 6, wherein a thickness in mm of said plate electrode extends in a direction of the axis of said tube. 
     
     
       8. A color cathode ray tube according to claim 7, wherein said plate electrode has at least an aperture for a center electron beam, said aperture having a smaller dimension in a direction of said in-line arrangement than a dimension of a direction perpendicular to said direction of in-line arrangement. 
     
     
       9. A color cathode ray tube according to claim 8, wherein said aperture has an elliptical shape. 
     
     
       10. A color cathode ray tube equipped with an in-line electron gun comprising three cathodes for emitting three electron beams of an in-line arrangement toward a fluorescent screen, and a main lens for focusing said three electron beams on the fluorescent screen, said main lens comprising two cylindrical electrodes arranged in a spaced relationship in a direction of an axis of said tube, each of said two cylindrical electrodes having therein a plate electrode with a beam passing area, said plate electrode having a thickness in mm which extends in a direction of said axis of said tube, said two cylindrical electrodes having different voltages applied thereto, wherein the following inequalities are satisfied;   2S+14.6≦T≦25.3     S being a beam spacing in mm between central axes of said three electron beams at said main lens, and T being an outside diameter of a neck portion of a vacuum envelope housing said in-line electron gun in mm, wherein a distance from a center of a side electron beam to an inner wall at said neck portion at said main lens is at least about 4.8 mm, and wherein convergence drift is reduced.   
     
     
       11. A color cathode ray tube equipped with an in-line electron gun comprising three cathodes for emitting three electron beams of an in-line arrangement toward a fluorescent screen, and a main lens for focusing said three electron beams on the fluorescent screen, said main lens comprising two cylindrical electrodes arranged in a spaced relationship in a direction of an axis of said tube, each of said two cylindrical electrodes having therein a plate electrode with a beam passing area, said plate electrode having a thickness in mm which extends in a direction of said axis of said tube, said two cylindrical electrodes having different voltages applied thereto, wherein the following inequalities are satisfied;   2S+14.6≦T≦26.7     S being a beam spacing in mm between central axes of said three electron beams at said main lens, and T being an outside diameter of a neck portion of a vacuum envelope housing said in-line electron gun in mm, wherein a distance from a center of a side electron beam to an inner wall of said neck portion at said main lens is at least about 4.8 mm, and wherein convergence drift is reduced.   
     
     
       12. A color cathode ray tube equipped with an in-line electron gun comprising three cathodes for emitting three electron beams of an in-line arrangement toward a fluorescent screen, and a main lens for focusing said three electron beams on the fluorescent screen, said main lens comprising two cylindrical electrodes arranged in a spaced relationship in a direction of an axis of said tube, each of said two cylindrical electrodes having therein a plate electrode with a beam passing area, said plate electrode having a thickness in mm which extends in a direction of said axis of said tube, said two cylindrical electrodes having different voltages applied thereto, wherein the following inequalities are satisfied;   2S+14.6≦T≦28.1     S being a beam spacing in mm between central axes of said three electron beams at said main lens, and T being an outside diameter of a neck portion of a vacuum envelope housing said in-line electron gun in mm, wherein a distance from a center of a side electron beam to an inner wall of said neck portion at said main lens is at least about 4.8 mm, and wherein convergence drift is reduced.   
     
     
       13. A color cathode ray tube equipped with an in-line electron gun comprising three cathodes for emitting three electron beams of an in-line arrangement toward a fluorescent screen, and a main lens for focusing said three electron beams on the fluorescent screen, said main lens comprising two cylindrical electrodes arranged in a spaced relationship in a direction of an axis of said tube, each of said two cylindrical electrodes having a common single opening for said three electron beams at opposing ends thereof and having therein a plate electrode with a beam passing area, said plate electrode having a thickness in mm which extends in a direction of said axis of said tube, said two cylindrical electrodes having different voltages applied thereto, wherein an outside diameter of a neck portion of a vacuum envelope housing said in-line electron gun is substantially 24.3 mm, wherein a distance from a center of a side electron beam to an inner wall of said neck portion at said main lens is at least about 4.8 mm, and wherein convergence drift is reduced. 
     
     
       14. A color cathode ray tube according to any one of claim 10 to claim 13, wherein said plate electrode has at least an aperture for a center electron beam, said aperture having a smaller dimension in a direction of said in-line arrangement than a dimension of a direction perpendicular to said direction of said in-line arrangement. 
     
     
       15. A color cathode ray tube according to claim 14, wherein said aperture has an elliptical shape.